A system and method for executing a regular expression query against a large data repository such as the World Wide Web includes an index engine that constructs multigram indices based on regex. A first high supply voltage and a low supply voltage are coupled to the first inverter. When the second situation is detected, the differential PWM signal including a plurality of pulses each having a gradually reduced width and the subsequent pulse train of no signal is generated and, at the same time, the generated pulses are sent to the amplifier via the multiplexer. The seal is removable to make a fiber optic communications linkage without cleaning the end face of the optical ferrule.